In recent years, cars equipped with airbag devices installed in, for example, the steering wheel and the instrument panel are widely used to protect occupants in the driver's seat and the passenger seat during a vehicle collision, an emergency situation, or the like. Such an airbag device, upon detection of a vehicle collision or in a similar situation, activates an inflator to supply gas into an airbag to inflate and deploy the airbag. Thus, the occupant's head or the like, moving toward the front of the vehicle, is received and restrained by the inflated and deployed airbag so as to be protected from the collision impact or the like.
As an example of such an airbag device, an airbag device having a gas rectifying member that controls and rectifies the flow of gas generated by an inflator and guides the gas to a predetermined position in the airbag is conventionally known (see Patent Document 1).
FIG. 15 is a cross sectional view schematically showing the structure of the conventional airbag device.
As shown in the figure, the airbag device 100 includes an airbag cover 116, an ornamental member 140 disposed on the occupant side thereof (the left side in the figure), an inflator 130 and an airbag 110 that are disposed in the airbag cover 116, and the like. The airbag device 100 is installed into, for example, the central portion of the steering wheel (not shown) of a vehicle.
The airbag cover 116 has a substantially bowl shape that can be split in conjunction with inflation and deployment of the airbag 110. The ornamental member 140 is disposed in a recess 116A formed on the occupant side. Between a base plate 124 attached on the other side (the right side in the figure) and the airbag cover 116 are accommodated a part of the inflator 130, the airbag 110, and the like. The inflator 130 is fitted to a hole (an opening) formed substantially at the center of the base plate 124 and is fixed to the base plate 124 in such a manner that one side thereof, having a plurality of gas discharge ports 130A, is inserted into the airbag cover 116.
The airbag 110 has an attachment hole for the inflator 130 and is disposed on the outside (outer peripheral side) of the inflator 130 attached thereto, in a folded state such that it can be inflated by the gas from the inflator 130. The periphery of the attachment hole of the airbag 110, disposed in this manner, is sandwiched between a cushion ring 122 inserted therein and the base plate 124 and is retained. Thus, the airbag 110 is fixed so as to cover the inflator 130. Furthermore, the airbag 110 includes a substantially bag-shaped airbag body 110A that is inflatable and deployable and a substantially tubular tether belt 110B that controls, for example, the extension length of the airbag body 110A (hereinafter, a “tubular tether belt”). The airbag 110, which is sequentially folded in an accordion shape toward the occupant side (toward the left in the figure), is accommodated in the airbag cover 116.
In this state, the airbag 110 is substantially entirely covered with the holding member 114, except for a portion near the inflator 130, so as to be wrapped from the outer surface side. A gas rectifying member 112 is disposed on the inner surface side between the airbag 110 and the inflator 130. The gas rectifying member 112 rectifies gas generated by the inflator 130 during inflation and deployment of the airbag 110, adjusts the outflow direction thereof in a predetermined direction, and guides the gas inside the airbag 110. At the same time, the gas rectifying member 112 also functions as an airbag protection member that protects the airbag 110 from the gas. The gas rectifying member 112 of the airbag device 100 rectifies the gas generated by, for example, the inflator 130 and guides the gas to the vicinity of a portion to be inflated at the initial stage of deployment of the airbag 110. Thus, the deployment characteristics of the airbag 110 are improved to enhance the occupant protection function.
Herein, in the conventional airbag device 100, the gas rectifying member 112 is formed in a disc shape (circular shape) having a hole substantially at the center, to which the inflator 130 can be inserted. The gas rectifying member 112 is disposed inside the airbag 110 so as to be concentric with the outer periphery of the above-described inflator attachment hole, and is attached to the airbag 110 through the cushion ring 122. Accordingly, the gas rectifying member 112, together with the airbag 110, is retained between the base plate 124 and the cushion ring 122 and is fixed, and an outside portion extending from the retained portion (a gas-flow guide portion) is disposed so as to extend along the inner surface (inner periphery) of the folded airbag 110.
Furthermore, the gas rectifying member 112 is already attached to the inside of the airbag 110 when the airbag 110 is folded in the above-described manner and, thus, is mounted to a folding device together with the airbag 110. The folding device for folding the airbag 110 retains the airbag 110 and the gas rectifying member 112 at a predetermined position using the cushion ring 122 and stretches the airbag body 110A and the tubular tether belt 110B upward so that they have a substantially tubular shape as a whole. From that state, the airbag 110 and the gas rectifying member 112 are pushed downward to be folded.
After the airbag 110 is folded vertically in an accordion shape and is compressed to a predetermined state by, for example, compressing the respective portions thereof downward in a folded manner, the airbag 110 is entirely covered with the holding member 114 and is securely held so that its folded shape is not destroyed. Then, the gas rectifying member 112 in the airbag 110 is disposed at a predetermined position in the airbag 110, as described above, completing the folding operation of the airbag 110.
This conventional airbag device 100 has, however, a tendency that, when the airbag 110 is folded, the gas rectifying member 112 is tucked between the folded portions of the airbag 110 and is folded in an accordion shape with the airbag 110, and substantially the entirety thereof is tucked into the airbag 110. Therefore, when the gas rectifying member 112 is disposed in the above-described manner, substantially the entirety of the gas rectifying member 112, sandwiched between the airbag 110, needs to be pulled out from between the airbag 110. At the same time, because the airbag 110, covered with the holding member 114, is held in a compressed state, the gas rectifying member 112 is relatively tightly sandwiched between the airbag 110. This makes the above-described pulling-out operation very difficult.
As has been described above, the conventional airbag device 100 has a problem in that the operation to dispose the gas rectifying member 112 in the airbag 110 is complicated and requires significant effort, manpower, time, and the like, thereby lowering the operation efficiency. In conjunction with this, the assembly operation of the airbag device 100 becomes difficult, and the operation efficiency thereof tends to be lowered.    Patent Document 1: Japanese Unexamined Patent Application Publication No. 2006-341716